Method of attaching labels on rotary abrasive discs

ABSTRACT

A method of attaching labels on rotary abrasive discs is disclosed. In a process for fabricating a rotary abrasive wheel which comprises placing grindstone material including thermosetting binder flat in a mold cavity, followed by compression molding the material and causing the moulded product to set by heating, the method includes positioning a label of material capable of withstanding the heating temperature along either surface of the grindstone material placed in the mold, prior to the compression molding step, and subsequently subjecting the label together with the grindstone material to compression in the direction of thickness thereof.

United States Patent 1191 Shimizu METHOD OF ATTACHING LABELS ON ROTARY ABRASIVE DISCS Inventor: Yozo Shimizu, 10-22 Funabori 5,

chome, Edo'gawa-ku, Tokyo, Japan Filed: May 26, 1971 Appl. No.: 147,044

[30] Foreign Application Priority Data May 29, 1970 Japan 45-46243 US. Cl. 51/206 R, 51/209 R, 51/293- Int. Cl B24d 5/00, B24d 5/12 Field of Search 425/289, 109, 116, 293;-

51/209 R, 206 R, 209 NF References Cited UNITED STATES PATENTS 2/1900 Spchn 51/206 NF 6/1966 Holdash 51/206 R 10/1969 Damm et a1. 425/116 [111 3,805,457 1 Apr. 23, 1974 3,528,127 9/1970 Damm et al. 425/116 2,397,101 3/1946 Goepfert 51/298 X 3,526,063 9/1970 Cook 51/206 NF Primary Examiner-Othell M. Simpson [5 7] ABSTRACT A method of attaching labels on rotary abrasive discs is disclosed. In a process for fabricating a rotary abrasive wheel which comprises placing grindstone material including thermosetting binder fiat in a mold cavity, followed by compression molding the material and causing the moulded product to set by heating, the method includes positioning a label of material capable of withstanding the heating temperature along either surface of the grindstone material placed in the mold,- prior to the compression molding step, and subsequently subjecting the label together with the grindstone material to compression in the direction of thickness thereof.

3 Claims, 3 Drawing Figures VPATENTEDAPRZSIHH 31805457 INVENTOR.

yozo sm/mzu M WM ATTORNEYS SPECIFICATION The invention relates to a method of presenting letters, characters or the like on a rotary abrasive wheel, and more particularly to a method for attaching a label or similar material to a rotary abrasive disc that is used for metal cutting and other purposes.

Presentation of trademark and/or specification o goods is conventional also in the art of rotary abrasive wheel as in other fields of goods. It is customary to apply a label to the surface of a finished abrasive wheel by suitable adhesive. However, this turns out to be disadvantageous where the label swells even slightly from the surface of the abrasive wheel, which causes the label to be torn off peripherally upon contact with tools or other objects during shipment or mounting on a machine. Otherwise, the label is also likely to be torn off gradually by a great wind resistance encountered during rotation of the wheel which can be effected as high a rate as 2,000rpm. Once a small portion of the label is torn off, the label is subjected to an increased wind resistance which rapidly causes further tearing off. In addition, detachment of the label may result in a loss of dynamic balance of the abrasive wheel or loosening of the wheel mounting where the wheel has'a small thickness of a few millimeters and is thrown into a high speed rotation, thereby causing unbalanced rotation. Unbalanced or unsteady rotation of the rotary abrasive wheel will not only interfere with precision finishing, but may lead to serious results such as its fracture or injure to operating personnel. To provide a presentation free from such drawbacks, it would occurto use a stronger adhesive or stamping technique, butit is seen that these are not satisfactory solutions in view of the roughened grindstone surfaces.

Therefore it is an object of the invention to provide a method of attaching a label to a rotary abrasive wheel which can eliminate the above disadvantages involved with the prior art abrasive wheels.

It is a specific object of the invention to provide a method whereby a lavel can be attached completely level with the surface of the abrasive wheel without producing any swelling of the label therefrom.

It is a further object of the invention to provide a method of attaching a label to a rotary abrasive wheel whereby the label can be held in place in a simple operation during the fabrication of the abrasive wheel itself.

In practizing the invention, a rotary abrasive wheel is obtained in which a label is embedded in the body of the abrasive wheel, but leaving an exposed presentation surface which is precisely level with the wheel surface. Thus, with such an abrasive wheel, the label cannot be digged peripherally or subjected to wind resistance during use. Where such an abrasive wheel is clamped by a pair of flanges of an associated machine from above the label, the wheel remains quite free from the influence of the label.

.Above and other objects, features and advantages of the invention will become apparent from the following description of particular embodiments thereof shown in the drawings, in which:

FIG. 1 shows, in section, a mold used for carrying out the method of the invention and grindstone material placed therein, a press mold being also shown in singledot chain lines,

FIG. 2 is a fragmentary section of a rotary abrasive wheel with label, fabricated in the manner illustrated in FIG. 1, and

FIG. 3 is a similar view to FIG. I, but illustrating a slightly modified manner.

As is known, grindstone material is a particulate mixture comprising fine particles of abrasive material and thermosetting binder such as phenol resin. In order to solidify the material into an abrasive wheel, the material is placed and compression molded in a mold, and the molded product is heated to cause the binder contained therein to set. Referring to the drawings, there is shown a mold 1 having a cavity 2 ofa desired volume. The mold 1 includes a projection 3 located centrally in the cavity for forming a mounting hole 10 that is to be fitted on a machine member in order to secure an abrasive disc 9 formed thereon. Unlike conventional molds used in casting synthetic resin, the mold l is associated with a press mold 11 that conforms to the cavity 2, for the purpose of compression molding the particulate fluid grindstone material to produce a compression product.

In the manner of operation illustrated in FIG. 1, a proportion of the total quantity of the grindstone material, indicated at 4, is initially deposited substantially uniformly on the bottom of the mold cavity 2, and on the deposit is placed a strengthening material 5 which generally is a network of glass fibre. Then the remainder of the grindstone material,-6, is deposited from above on the strengthening material 5 substantially uniformly. It is a simple mattertolay the grindstone material all over the cavity bottom to a uniform thickness.

A label that is applied in accordance with the invention is shown at 7, and is placed on the top layer 6 of grindstone material. While it is disposed around the projection 3 and centrally in the cavity 2 in this particular embodiment, it should be obvious that the label may be disposed at any other location. According'tothe invention, subsequent to disposition of the label 7, the whole lamination including the label 7 and the layers of grindstone'material (4 and 6) as well as the strengthening material 5 is subjected to compression with the press mold 11. Usually the compression takes place under the pressure of 100 to 200 Kg/cm. The compression product includes the material 5 compacted in a sandwiched from between layers of grindstone material, and in the product is embedded the label 7 which is exposed at its surface alone. Since the compression product obtained at this stage is still brittle, and the label 7 is not firmly bonded with the product. Now the product is removed from the mold 1 and is heated in a suitable oven to the setting temperature of the binder used, whereupon the binder is melted and then set,

firmly bonding the particles of the product together and strongly bonding the label 7 with the product. The heating for causing the binder contained in the grindstone material to set is conducted to a temperature which depends on the type of binder, but generally this temperature is around 200C. As a consequence, both the strengthening material and the label material must be capable of bearing such a temperature. However, it is a simple matter to choose a material that is suitable for use as a label from a variety of materials withstand ing temperatures on the order of 200C. Any suitable choice can be made from aluminium foil, paper, nonwoven fabric and synthetic resin film, for example.

it will be appreciated that the label placed on the layer of grindstone material 6 may be either a printed label or blank one for later presentation. Where a printed label is used in the process of compression molding, the ink used in printing the label must be heat resistant as is the label material.

FIG. 3 shows another manner of operation wherein another label 8 is placed on the bottom of the cavity 2 initially before the bottom layer of grindstone material 4 is deposited thereon. Upon compression molding, the label 8 is embedded in the body of abrasive wheel with its surface exposed and level with the wheel surface, as in case of FIG. 1.

From the foregoing, it will be apparent that the invention has provided a novel method of attaching a label to a rotary abrasive wheel whereby the label is embedded in the body of the abrasive wheel with its exposed surface level with the surface of the wheel. The embodiments described herein are illustrative only, and the appended claims are intended to cover all such modifications and changes thereof as fall within the scope and spirit of the invention.

What is claimed is:

1. A process for fabricating a rotary abrasive wheel comprising depositing a grindstone material including a thermosetting binder uniformly in a mold cavity of a shape for forming said wheel, separately preparing a lable of a heat-resistant material with printing idicia thereon of a heat-resistant ink, positioning said label along at least one surface of said grind-stone material deposited in said mold, pressing said grindstone material and binder together with said label by said mold forming said wheel with said label in one face thereof, removing the compressed material with .said label thereon from said mold, heating said compresses material with said label therein bonding said lable to said compressed material with the aid of said thermosetting binder simultaneously when said thermosetting binder melts and firmly bonds the particles of said compressed grindstone material and keeping clear the printing on said label during said heating.

2. A method according to claim 1, including placing said label on the bottom of the mold cavity before depositing the grindstone material so as to place the label along the lower surface of the grindstone material.

3. A method according to claim 1, including placing said label on the upper surface of the grindstone material after the latter has been deposited in the mold cavlty 

1. A process for fabricating a rotary abrasive wheel comprising depositing a grindstone material including a thermosetting binder uniformly in a mold cavity of a shape for forming said wheel, separately preparing a lable of a heat-resistant material with printing idicia thereon of a heat-resistant ink, positioning said label along at least one surface of said grind-stone material deposited in said mold, pressing said grindstone material and binder together with said label by said mold forming said wheel with said label in one face thereof, removing the compressed material with said label thereon from said mold, heating said compresses material with said label therein bonding said lable to said compressed material with the aid of said thermosetting binder simultaneously when said thermosetting binder melts and firmly bonds the particles of said compressed grindstone material and keeping clear the printing on said label during said heating.
 2. A method according to claim 1, including placing said label on the bottom of the mold cavity before depositing the grindstone material so as to place the label along the lower surface of the grindstone material.
 3. A method according to claim 1, including placing said label on the upper surface of the grindstone material after the latter has been deposited in the mold cavity. 